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Bernd D. Heumesser and Ralf-Dieter S himkat Wilhelm-S hi kard-Institute for Computer S ien e University of T ubingen, Germany fheumesser, s himkatg informatik.uni-tuebingen.de Abstra t This papers shows the deployment of the pro essing and omputational fa ilities of Prolog to query on XML do uments and to reason about their ontent. Based on a ase study we show that it is feasible and useful to deploy Prolog in omplex, mobile agent environments. We introdu e a rule-based system omponent whi h reasons about XML do uments and their ontent respe tively. It provides a state-of-the-art World Wide Web interfa e to onne t to multi agent appli ations. 1 Introdu tion and Motivation XML [1℄ is a versatile markup language for labeling information ontent of diverse data sour es. It is a ommon standard and used for storing and ex hanging data. Generally, extra ting data, pro essing it, and nally applying omputation on it with respe t to some appli ation or business logi is a major issue in developing XML-related appli ations. Common XML query languages [6, 4, 11℄ support extra tion and aggregation of data stored in XML appli ations. However, they only provide limited builtin omputation fa ilities. Therefore, most XML-based appli ations deploy the ri h omputation apabilities of soalled appli ation servers. Typi ally, an appli ation server is implemented in an obje t-oriented programming language. Arbitrary appli ation or business logi an be implemented to pro ess and ompute on XML do uments. The ommon approa h is hara terized by the transformation of XML do uments into the respe tive representation of the appli ation server's programming language. For example, by using Java [8℄ XML do uments are basi ally transformed into Java obje ts. In this paper, we deploy the pro essing and omputational fa ilities of Prolog [14℄ to query on XML do uments and to reason on their ontent. In our ase study we show the potential bene ts of transforming XML do uments into Prolog terms. The ore omponent of our ase study is a mobile and autonomous agent system whi h is used for a distributed, irregular symboli omputation. Basi ally, we established a ruleT-Systems Do ument Management Solutions IMA Prolog Terms